Asian prince (4)
'asian prince' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rajah that I've seen before include "Asian ruler" , "Hindu ruler" , "Former Indian ruler" , "Indian king or prince" , "Royal Indian male" .)
(Other definitions for khan that I've seen before include "Title given in parts of Asia to important people" , "Title taken by ancient Mongol emperors, such as Genghis" , "Title of rulers and officials in central Asia" , "Eastern potentate" , "Ghengis for one" .)